Such an apparatus is disclosed in published French patent application No. 2 444 719. It may be used, for example, for localized cold working the surface of steel in order harden it.
In this prior apparatus, the percussion tool is in a single block and when the spherical end becomes worn, the entire tool must be replaced which is expensive since such a tool requires special fabrication. Further, this apparatus provides considerable recoil in use which makes it difficult to handle.